A Novel Electrochemical Sensor for Formaldehyde Based on Platinum Nanoparticle/L-Alanine Modified Glassy Carbon Electrode

Abstract

In this paper a novel and sensitive electrochemical sensor for the detection of formaldehyde was developed based on the platinum nanoparticles and L-alanine modified glassy carbon electrode. The sensor was fabricated by two steps. Platinum nanoparticles were immobilized on the electrode via electrodeposition method firstly, then the L-alanine was modified on the electrode by self-assembly method. The structure and morphologies of the Platinum nanoparticles were characterized by SEM and TEM. The electrocatalytic activity of the PtNP-L-alanine/GC electrode for formaldehyde detection in alkaline media was investigated via a series of electrochemical measurements. The PtNP-L-alanine/GC electrode show very high electrochemical activity toward formaldehyde. The oxidation peak current had a linear relationship with the formaldehyde concentration in the 0.3 µmol dm-3 to 4.0 mmol dm-3 range (R=0.9998), while the detection limit was estimated to be 34 nmol dm-3 (S/N=3). Such high sensitivity was attributed to the large surface area of the highly dispersed nanoparticles for electrocatalytic reaction and the fast electron transfer in the composite electrode. It demonstrated that glassy carbon electrode modified by platinum nanoparticles and L-alanine was suitable for the determination of formaldehyde.